# coding: utf-8

# # Behavior of Elimination Matrices

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import numpy as np


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n = 4


# ----------------
# Let's create some elimination matrices:

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M1 = np.eye(n)
M1[1,0] = 0.5
M1


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M2 = np.eye(n)
M2[3,0] = 4
M2


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M3 = np.eye(n)
M3[2,1] = 1.3
M3


# -------------------
# Now play around with them:

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M1.dot(M2)


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M2.dot(M1)


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M1.dot(M2).dot(M3)


# BUT:

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M3.dot(M1).dot(M2)